The move comes only a short time after another large grocery chain, SUPERVALU, announced a similar transition. Many other companies, such as McDonald's, have also announced a switch to cage-free eggs in the last year.

“Our customers and associates count on Walmart and Sam’s Club to deliver on affordability and quality, while at the same time offering transparency into how their food is grown and raised,” said Kathleen McLaughlin, chief sustainability officer at Walmart.

“Our commitment to transition to a cage-free egg supply chain recognises that expectation and represents another step we are taking to improve transparency for food we sell in our US stores and clubs.”

Walmart said it will require 100 per cent of shell egg suppliers to be certified and fully compliant with United Egg Producers (UEP) Animal Husbandry Guidelines or an equivalent standard and monitor compliance via annual third party.

Commenting on the SUPERVALU announcement, Humane Society senior director of food policy Josh Balk said: “SUPERVALU’s policy is going to improve life for millions of animals. We appreciate the company’s work with us and urge the few remaining top grocers lacking cage-free commitments to join the rest of their industry in getting chickens out of cages.”